ams OSRAM | AS5311-ATST

A Hall effect sensor is a transducer that varies its output voltage in response to changes in magnetic field. Hall sensors are used for proximity switching, positioning, speed detection, and current sensing applications.

In its simplest form, the sensor operates as an analogue transducer, directly returning a voltage. With a known magnetic field, its distance from the Hall plate can be determined. Using groups of sensors, the relative position of the magnet can be deduced.

Electricity carried through a conductor will produce a magnetic field that varies with current, and a Hall sensor can be used to measure the current without interrupting the circuit. Typically, the sensor is integrated with a wound core or permanent magnet that surrounds the conductor to be measured.

The AS5311 is a single-chip IC with integrated Hall elements for measuring linear or rotary motion using multi-pole magnetic strips or rings. This allows the usage of the AS5311 in applications where the Sensor IC cannot be mounted at the end of a rotating device (e.g. at hollow shafts). Instead, the AS5311 is mounted off axis underneath a multi-pole magnetized ring or strip and provides a quadrature incremental output with 256 pulses per pole period at speeds of up to 0.65 meters/sec. A single index pulse is generated once for every pole-pair at the index output. In addition, a digital output is available providing 12-bit absolute information within one pole-pair, resulting in a resolution of 0.488 µm from 0 - 2 mm.

The absolute output is available over a serial interface and on a PWM output.

The magnet pole pair length is 2.0mm (1.0mm north pole / 1.0mm south pole).

The AS5311 is ideal for high resolution linear motion and off-axis rotation measurement in applications such as

• micro-actuator feedback
• servo drive feedback
• electrical motors
• robotics
• replacement of optical encoders

The AS5311 is available in a small 20-pin TSSOP package, is specified for an operating ambient temperature of -40° to +125°C and is the highest resolution linear magnetic encoder available in the market.